Neurophysiology - the autonomic NS

Question 1

What does your ANS help maintain

Answer 1

Homeostasis -

blood pressure, body temp, water balance

Question 2

target organs of ANS

Answer 2

in the thoracic or abdominopelvic cavities

+ body wall (cutaneous blood vessels, glands etc.)

Question 3

how many motor neurons go from the spinal cord to a muscle in the somatic NS

Answer 3

one or monosynaptic

Question 4

how many motor neurons go from the spinal cord to a muscle in the autonomic NS and where do they synapse

Answer 4

two (two motor neuron chain) - connected by a synapse at an autonomic ganglion

Question 5

3 divisions of the sympathetic NS

Answer 5

Sympathetic chain ganglia
collateral ganglia
renal medulla

Question 6

two types of ganglionic neurons preganglionic neurons can synapse with in the sympathetic ns

Answer 6

either ones that connect to an organ / muscle/tissue
or modified ganglionic neurons which secrete their own neurotransmitters into the bloodstream which acts like a hormone but with a stronger effect which lasts5-10x longer, reaches all cells in body (as long as they have the right receptor to respond to the hormone) leading to 100% increase in metabolic rate

Question 7

what number is the vagus nerve and why is it important

Answer 7

cranial nerve #X and it controls about 75% of parasympathetic outflow or responses

Question 8

three common conditions that might arise from ageing and lack of responsiveness of the ANS

Answer 8

Constipation
orthostatic hypotension - low blood pressure specifically when you stand up
decreased ability to thermoregulate

Question 9

what do all ANS preganglionic fibres release

Answer 9

acetylcholine (Ach)

Question 10

what do parasympathetic postganglionic fibres release

Answer 10

Ach

Question 11

what neurotransmitter does the sympathetic postganglionic fibres release

Answer 11

most release norepinephrine (NE) (noradrenaline)

some release Ach

Question 12

What do neuroendocrine cells of the adrenal medulla release

Answer 12

80% epinephrine / adrenaline

20% norepinephrine

Question 13

What are Ach and norepinephrine releasing fibres called

Answer 13

cholinergic and adrenergic fibres

Question 14

two types of receptors within cholinergic receptors

Answer 14

nicotinic - on all ganglionic neurons and respond to acetylcholine released by preganglionic neurons, always excitatory - always get an excitatory postsynaptic potential
muscarinic - located on all parasympathetic target organs, can be excitatory or inhibitory, g-protein coupled receptors

Question 15

Receptors that respond to epinephrine or norepinephrine

Answer 15

adrenergic alpha (a1 a2) or beta (b1 b2 b3)
found on target organs of sympathetic
either excitatory or inhibitory